Asst. Prof. Dr. Prapun Suksompong

prapun@siit.tu.ac.th

1

EC Talk

Office Hours: (BKD 3601-7)

Wednesday 9:30-11:30

Wednesday 16:00-17:00

Thursday 14:40-16:00

Outline

2

Courses

ECS 452: Digital Communication Systems

ECS 455: Mobile Communications

ECS 456, 477

Senior projects

Courses: General Information

3

Annotated lecture notes and slides from previous years are available at prapun.com http://www2.siit.tu.ac.th/prapun/ecs455/ http://www2.siit.tu.ac.th/prapun/ecs452/

Tentative grading policy

No project

Assignments 5%

Class Participation and Quizzes 15%

Midterm Examination 40%

Final Examination 40%

Asst. Prof. Dr. Prapun Suksompongprapun@siit.tu.ac.th

Course Introduction

4

Mobile CommunicationsECS 455

Office Hours: (BKD 3601-7)

Wednesday 9:30-11:30

Wednesday 16:00-17:00

Thursday 14:40-16:00

Marty Cooper: Cellphone Inventor

5

1973

Motorola DynaTAC prototype

Weighed nearly two kilos

Cost approximately $1 million for Motorola to produce.

20 minutes battery life

[http://gizmodo.com]Not a problem because you could

not hold it up for twenty

minutes; it was so heavy.

iPhone 5s Teardown

6

Qualcomm MDM9615M LTE Modem

Qualcomm WTR1605L

LTE/HSPA+/CDMA2K/TDSCDMA/EDGE/GPS transceiver

iPhone 5s Spec

7

Cellular:

GSM

ECS455: Topics

8

1. “Wireless” Communications: Problems and Solutions.

2. “Cellular” Communications: Motivation and Analysis.

3. Multiple Access Schemes: How can many users share communication resources?

4. Spread Spectrum Communications including CDMA (2G-3G)

5. OFDM systems (3.5-4G)

6. Communication techniques in GSM, GPRS, EDGE, UMTS (W-CDMA), WiMAX (OFDMA), LTE (SC-FDMA)

Asst. Prof. Dr. Prapun Suksompongprapun@siit.tu.ac.th

Course Introduction

9

Digital Communication Systems

ECS 452

Office Hours: (BKD 3601-7)

Wednesday 9:30-11:30

Wednesday 16:00-17:00

Thursday 14:40-16:00

10

“The fundamental problem of

communication is that of

reproducing at one point

either exactly or approximately a

message selected at another point.”

Shannon, Claude.

A Mathematical Theory Of

Communication. (1948)

Basic elements of communication

11

Noise Source

ReceiverTransmitterInformation

SourceDestinationChannel

Received

SignalTransmitted

SignalMessage Message

Digital Communication

12

Source

Encoder

Channel

Encoder

Channel

Channel

Decoder

Source

Decoder

010100

010100

Bin

ary

Inte

rfac

e

Input

Output

Take the bits from one place to another.

Binary data stream (sequence of data) without

meaning (from channel viewpoint).

This is the major layering of all digital communication systems.

Know the probabilistic

structure of the input

source.

+ noise &

interference

Waveform sequence symbols bits

General Ideas

13

Extension of Principles of Communications (ECS332) and

Probability and Random Processes (ECS315)

Focus more on

performance analysis (bit error rates),

optimal receivers, and

limits (information theoretic capacity).

ECS 452 Topics

14

Random noise process

Optimal Receivers

Digital modulation techniques and their performance

Source coding and entropy

Information theory (capacity)

Channel coding

Wireless communications

MIMO: Multiple-Input Multiple-Output

OFDM: Orthogonal-Frequency Division Multiplexing

ECS456: Optical Communication

15

Prerequisite: ECS233 (Electromagnetics)

Description: Characteristics of lightwave propagation in optical

fibers.

Types of optical fibers.

Optical transmitters and receivers.

Optical filters and amplifiers.

Optical components: optical divider and combiner, coupler, lens switches.

Optical communication systems.

Coding, multiplexing, demultiplexing, switching, and wavelength conversion.

Optical network architectures.

Type: Lecture 80% Project 20%

Note: Good for better job opportunity

ECS477 Signal Processing for

Communication Systems

16

Prerequisite: ECS472 (DSP)

Description: Project-Based

Speech coding and decoding

image coding and decoding

filter banks and multi-rate signal

processing

channel estimation/ equalization/

synchronization

array processing and power spectral

estimation

adaptive filtering

Type: Lecture 50% Project 50%

Note: MATLAB programming intensive,

good for graduate study.

Assoc. Prof. Dr. Chalie Charoenlarpnopparut

chalie@siit.tu.ac.th

Asst. Prof. Dr. Prapun Suksompong

prapun@siit.tu.ac.th

17

Senior Projects

At a glance

18

MATLAB Simulations

Wireless Communications

1. OFDM, MIMO, Multi-User Techniques

2. Visible light communication (VLC)

3. 60 GHz Communication

4. Game theory in wireless and communication networks

5. RFID Localization

WiFi: IEEE 802.11

19

802.11: PHY Data Rates

20

Wireless Digital Comm. System

21

Encoder0100101010001 Decoder

0100101010001

Transmitter (Tx) Receiver (Rx)

Wireless Channel (SISO)

MIMO: 802.11n

22

(Multiple Input Multiple Output)

Encoder0100101010001 Decoder

0100101010001

y

zy x H

NoiseChannel Matrix

x

Wireless Channel (MIMO)

MIMO/SDM

23

Encoder0100101010001

Decoderyx

Problem: Interference among transmitting antennas

Solution: Pre-process (pre-code) the transmitted signals

Advantage: Space-division multiplexing (SDM)Transmit multiple independent data streams or

spatial streams on different antennas

1110101010101

0000101111000

0100101010001

1110101010101

0000101111000

(SU-MIMO)

802.11agn: 54 Mb/s to 600 Mb/s

24

802.11ac PHY Data Rates

25

Multiple Users: Downlink MU-MIMO

26 4(2,2) System

STA1

STA2

Encoder

Encoder

0100101010001

0100101010001

0100101010001

0100101010001

x

1s

2s

1y

2y

2 2

1

2

1 1zy x

y zx

H

H

To: STA1

To: STA2

(in the bedroom)

(in the living room)

At a glance

27

MATLAB Simulations

Wireless Communications

1. OFDM, MIMO, Multi-User Techniques

2. Visible light communication (VLC)

3. 60 GHz Communication

4. Game theory in wireless and communication networks

5. RFID Localization

Radio-frequency spectrum

28

Commercially exploited bands

c f

Wavelength

Frequency

83 10 m/s

[http://www.britannica.com/EBchecked/topic-art/585825/3697/Commercially-exploited-bands-of-the-radio-frequency-spectrum]

Note that the freq. bands are

given in decades; the VHF band

has 10 times as much frequency

space as the HF band.

29

Thailand Freq. Allocations Chart

30http://www.ntc.or.th/uploadfiles/freq_chart_thai.htm

Thailand 2.1GHz Auction

31

4.5bn baht per license (freq chunk)

1 license (chunk) = 5 MHz (UL) + 5 MHz (DL)

450 million baht per MHz

30 million baht per MHz per year

Limitations/constraints of RF

Communications

32

Radio wave resource

Limited (bandwidth), Scarce, Expensive, Regulated

Capacity: We are simply running out of spectrum.

Can’t keep up with the demand of wireless data transmissions

Interference with other products/systems

Have to switch off your mobile phone during flights.

Mobile phones and WiFi’s are undesirable in certain parts of hospitals, especially around MRI scanners and in operating rooms.

Security

Radio waves penetrate through walls. They can be intercepted.

And God said, ְיִהי אֹור

33

VLC and LEDs

34

Visible Light Spectrum (VLC)

Widespread deployment of Light-Emitting Diodes (LEDs) for energy conservation in general lighting.

Substitute of conventional incandescent and fluorescent lamp due to its lower power consumption, high efficiency and longer lifetime.

Information can be modulated (at high-speed) into the instantaneous optical intensity. Provide a data channel in addition to the illumination, which is

provided by the average signal level. Convergence of illumination and communications.

VLC is now regarded as one of the most important green communication technologies.

VLC: Advantages

35

Huge bandwidth

10,000 times larger than the radio waves spectrum.

Unregulated, license-free operation. No licensing fees.

High communication security. Easy to block.

No interference with sensitive electronic systems.

Safe

Light has been around for many millions of years. It has created us, has created life, has created all the stuff of life.

So it's inherently safe to use.

Availability: the existing lighting infrastructure can be used

Billions of light bulbs already installed.

Low-cost front-end devices

Possible Applications

36

Possible Applications

37

At a glance

38

MATLAB Simulations

Wireless Communications

1. OFDM, MIMO, Multi-User Techniques

2. Visible light communication (VLC)

3. 60 GHz Communication

4. Game theory in wireless and communication networks

5. RFID Localization

60 GHz Wireless Communications

39

Millimeter-wave (mm-wave) technology

Unlicensed band

One of the largest being allocated

At least 5 GHz of continuous bandwidth worldwide

Small form factor

Can be conveniently integrated into consumer electronic products.

Huge path loss

Enables higher-frequency reuse in each indoor environment.

Cognitive radios: Motivation

40

Back to radio-frequency spectrum

Traditional Rule: Allow predetermined licensed users the right to transmit at given frequencies. Frequency bands were sold at auction, bringing considerable revenue

to the government. Unlicensed users are regarded as “harmful interference.”

Radio-frequency resources are not fully utilized There exists a large number of frequency bands that have

considerable, and sometimes periodic, idle time intervals. For example, some TV stations do not work at night. Spectrum holes.

Cognitive radios

41

A revolutionary communication paradigm that can utilize the

existing wireless spectrum resources more efficiently.

New Assumption: Users are intelligent and have the ability to

observe, learn, and act to optimize their performance.

Game theory has been recognized as an important tool in

studying, modeling, and analyzing the cognitive interaction

process.

Game Theory

42

A branch of applied mathematics as well as of applied sciences.

A formal framework with a set of mathematical tools

To

study the complex interactions

analyze competition and cooperation

among interdependent rational players (having individual self-

interests.)

For more than half a century, game theory has led to revolutionary

changes in economics.

Three Nobel Prizes have been given in the economic sciences for

work primarily in game theory.

RFID Positioning and Localization

43

RFID = Radio Frequency

Identification

Want to link identification

information to location

The strength (and its changes) of

RF signals could be utilized to

locate and hence track objects.